minor narwhal
Quite a fair few people do often have some difficulty with this mission out there on the field, if you’re reading this and you spent a solid ten minutes scrubbing the bomb up against a set of double doors like an old man with a bar of soap and some rather lacking motor abilities:
YOU ARE IN LUCK MY FRIEND! 
First of all, regardless of where the map marker displays the mission objective to be, you are going to go in the direction parallel to the doors you’ve been trying oh so desperately to get through, the only way in to this desired building is via the overhanging bridge that connects the two, the bridge can be accessed through the building opposite to the one with the multiple sets of locked double doors.
Once you’ve made it around and into the opposite building, you’re gonna want to find a set of foundational steps (these can be found in the warehouse-like complex of the adjacent factory room) leading up to a sequence of lockers and desk cubicles. (There’s usually some goodies in here, take a quick look around!)
Now once you’ve made your way through this you are essentially right where you want to be! Cross that bridge and get to where your mission directs you, it’s fairly linear as you’ll find it branches down into a path of corridors, descend a few floors and you’ll find an armoured door that’s practically just BEGGING to be blasted open with that trusty homemade explosive you’ve been clinging onto! 
proud crescent
Let’s just add (spoilers) in the title of such guides. So that players are aware they are about to read info about a specific part of the game 
terse pollen
lofty cypress
mystic gull
muted yew